Web Site Backup Webpage

We all know that despite the best-laid plans, accidents or mishaps happen, so it is always a good idea to keep the Boy Scouts’ motto in mind.

Be prepared.

In the case of webmasters and web hosts, this applies to a number of concerns, including hacking attacks, network downtimes, and most particularly, to loss of data.

Data loss can result from a number of things, including hard drive failures, inadvertent deletion or even natural disasters such as hurricanes, floods or earthquakes. It is thus important for you (webmasters) to make sure that your web hosts have, not only appropriate data backup methods in place, but also a system for restoring them (even if the site has been deleted or in the event of migration to a different server).

There are different ways that web hosts protect web sites from data loss:

* Regular Onsite Backups – in which your files are saved to a separate storage device on a daily/weekly/monthly basis

This can be done several ways:
o RAID (Redundant Array of Independent Disks) – involves the configuration of hard disk drives to work together to increase performance and/or fault tolerance. It protects against data loss due to hard drive failure by using one of two techniques – mirroring and parity. An explanation for this can be found here.
o CD Backups – involves the compression and burning of data onto a CD
o Network Backups – involves the maintenance of a centralized backup system that allows your data to be dumped to a storage array directly through the network and is a convenient and seamless way to store your data without consuming your own disk space or unnecessarily consuming media
o Backup/Redundant Disk Drive (for dedicated servers) – each physical server could have a hard disk backup that runs every 24-hours; provides enhanced data protection when used in addition to a RAID Array: A disk drive may be placed on a controller separate from the RAID Array, and in the event of RAID controller failure, data restoration can be performed by accessing the backup disk drive. This process can be automated using automated scripts.
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Tape Backups – involves the use of data tapes to store your information; some factors to consider when putting together a tape drive configuration:
+ Amount of data to backup
+ Length of time to keep saved data before overwriting it
+ Type of backup to perform (incremental, differential, full copy, etc.)
+ Frequency of backup (daily, weekly, monthly, etc.)
* Off Site Backups: involves the duplication, compressed and transmission of your data to a remote location on a regular basis; work like regular tape backups but instead of sending backup data to a tape drive, the file is encrypted and sent over the Internet to multi homed data centers for immediate and safe storage away from your server’s location.

Reasons for doing offsite backups (even if you already have a tape backup system) include:
o Time savings – tapes are slow and sequential, which make it difficult to find files quickly
o Increased productivity – due to disk drives’ better read / write efficiency
o Lower cost – eliminates the need for expensive backup equipment (since you only need an Internet connection), as well as for in-house administrators (since the process is fully automated).

Technologies used in remote/offsite backups include:
o Blowfish encryption – a freely available 64-bit block cipher algorithm that runs faster than DES or Triple DES and comprises two parts:
+ Key expansion: expands the key from its original size (32-448 bits) into several subkey arrays that total 4168 bits
+ Encryption: uses a 16-round Feistel (a class of iterated block ciphers that calculate the cipher text by the repeated application of the same transformation or round function over the plaintext) network algorithm; data is split in two and the round function applied to half (using a subkey); output XORed with the second half and the two are swapped.
o FastBIT technology – an incremental backup technology using a complex algorithm; it (precisely) identifies changes made to any type of file since last backup; sends these changes (with minimal bandwidth) to the backup server; and combines them with the previous backup (upon receipt by the server) to form an identical copy of your current file
* Multiple Daily Backups: multiple daily backups or hourly backups can be done and your site placed on its own dedicated web server with continual redundant backup systems and data integrity checks.

In addition to multiple backup systems provided by your host, you should also maintain your own up-to-date copy of critical data for your own purposes at all times.